The present invention relates to a pattern transferring apparatus for manufacturing semiconductor devices or devices having a fine pattern such as MEMS (Micro Electro-Mechanical Systems) and, more specifically, to so-called photo-curing type nanoimprint lithography.
In a photo-curing type nanoimprint apparatus used for nanoimprint lithography, which has been disclosed in U.S. Pat. No. 6,334,960, a liquid ultraviolet (UV) curable resin as a resist is disposed between a substrate and a mold (original plate or template) having a relief pattern, and then the resist is cured by UV irradiation through the mold. The mold is released from the substrate after curing the resist, and the pattern-transferred resist thereby remains on the substrate.
Then, residual layer (base layer) of the resist are removed by executing RIE (reactive ion etching) on the pattern-transferred substrate. Thereby, a pattern is formed on the substrate.
Manufacturing of semiconductor devices is generally repeated at a high speed by Step-and-Repeat method or the like. Therefore, a long time to release the mold from the substrate (hereinafter, it is referred to as mold release) decreases throughput of the nanoimprint apparatus, furthermore productivity of the device.
In the field of injection molding, the following method to shorten an amount of time for mold release is known. FIG. 10A shows a mold-releasing method disclosed in Japanese Patent Laid-Open Application No. H11-333862.
FIG. 10A shows a die for forming an optical element that is an object of molding. 501a denotes a first die face for forming an effective diameter portion of the optical element, and 501c denotes a second die face for forming the peripheral edge of the optical element. 501 denotes an outer portion of the die.
In the second die face 501c and the peripheral portion 501, a through hole 501e is provided for taking outer air into the die. Introducing outer air into the border area between the resin (optical element) and the die through the through hole 501e, area which has been a vacuum state, decreases die-releasing force needed to release the die from the optical element. Furthermore, since the opening of the through hole 501e provides a starting point of die release, the die release can start smoothly, thereby making it possible to shorten the die-releasing time.
FIG. 10B shows a die-releasing method disclosed in Japanese Patent Laid-Open Applications No. 2003-222706 and 2003-222708. 511 denotes a die face for resin molding, and 510a and 510b denote protruded portions formed on the molded resin, which formed by depressed portions provided on the die. When viewed from the side of the die, the protruded portion 510a has an inclination and the protruded portion 510b has a rectangular shape. Stress for die release concentrates on the protruded portions 510a and 510b, and they therefore provide starting points of die release. This can decrease die-releasing force and shorten die-releasing time.
As described above, it is important to provide the starting point of mold release for facilitating the mold release. However, the die-releasing methods disclosed in Japanese Patent Laid-Open Applications No. H11-333862, 2003-222706 and 2003-222708 relate to resin molding of optical elements such as a lens, and they provide a starting point of mold release on the side of the lens, which does not exist on the lens surface but inevitably exists in the lens.
In contrast, the nanoimprint lithography brings the mold in contact with a planar object surface and transfers a pattern to areas adjacent to each other one after another. Therefore, the die-releasing methods disclosed in Japanese Patent Laid-Open Applications No. H11-333862, 2003-222706 and 2003-222708 cannot be applied to the nanoimprint lithography as they are.